Off airway navigation

[FOD]

How do you navigate in IMC to an airport that is off a major airway? What would you file since their are no airways? What altitude would you fly?

 

[HMR]

How do you navigate in IMC to an airport that is off a major airway? What would you file since their are no airways? What altitude would you fly?

Excellent question. Does the airport have an instrument approach or is it VFR only?

If you have a particular airport in mind, share it and we'll walk you through the flight plan.

 

[DrewBlows]

File direct to the airport from a fix along your route. If the airport is in radar coverage expect vectors, otherwise just go to the IAF and fly the approach. If it's not in radar coverage and is a ways off your course you could always navigate using dead reconing, you can verify your position using cross radials. Fly higher than the grid MORA (I think that's what Jeppesen calls it), and you'll be fine.

 

[FOD]

Did'nt really have any particular airport in mind. But, yeah i was assuming an airport with an instrument approach. Ok, for example on the 5,6 Low altitude enroute chart. If we were going from Winslow to Payson in IMC. My charts are pretty old, but looks like their is no feeder and Payson only has a GPS approach. How would we get there? What Altitude would we fly? and What would we file?

"If it's not in radar coverage and is a ways off your course you could always navigate using dead reconing, you can verify your position using cross radials"
How do you know if its radar coverage?

"Fly higher than the grid MORA (I think that's what Jeppesen calls it), and you'll be fine."
So you would you stay at the MORA until on on the approach then descend down in the hold?

 

[Singlecoil]

Well, in your example the airport has a GPS approach so the means to get there....(drum roll please) would be GPS direct. Ta-da.

What if you want to go IFR to an airport that doesn't have an approach, isn't on an airway, and you don't have a GPS? In that case the next question you ask yourself is: Is the airport within the operational service volume of a navaid? Look in the AFD to figure out what the class of nearby NDB's are, or check the chart for the class of nearby VOR's, then determine if the airport lies within the operational service volume (OSV) of one of the navaids. The front of the AIM spells out the different OSV's. If it lies within the OSV of a navaid, file direct the navaid, then direct the airport. Use your plotter to figure out what bearing or radial to fly and off you go.

 

[mnixon]

You can not self navigate to anything i.e. dead reckoning. You must always be radar vectored, on a published route, or going to a naviagtional fix. In your case, if in radar youll get vectored to the course, if no radar go to the FAF or feeder fix. You may not just navigate to the airport.

 

[DrewBlows]

You can not self navigate to anything i.e. dead reckoning. You must always be radar vectored, on a published route, or going to a naviagtional fix. In your case, if in radar youll get vectored to the course, if no radar go to the FAF or feeder fix. You may not just navigate to the airport.

I disagree. If you aren't in radar coverage you can use dead reckoning (technically speaking you can use it while in radar coverage, but why would you?). It's possible that I am wrong, I don't recall a regulation against dead reckoning, if one exists will you please post it?

 

[User546]

Allright, lets throw a bonus question in here.

Since we've got a healthy discussion going on about NAVIGATING to the off-airway fix - lets add this element to it:

When, and what method would you use to properly descend, and stay free of obstacles, prior to reaching the begining of your approach fix?

For instance, your cruising at 15,000 feet, your destination airport is at 800 feet, and the first segment of the approach calls for you to start at 2,500 feet. At what point, and what method would you use to determine when you could safely descend down prior to reaching the approach enviroment?

 

[Donsa320]

Allright, lets throw a bonus question in here.

Since we've got a healthy discussion going on about NAVIGATING to the off-airway fix - lets add this element to it:

When, and what method would you use to properly descend, and stay free of obstacles, prior to reaching the begining of your approach fix?

For instance, your cruising at 15,000 feet, your destination airport is at 800 feet, and the first segment of the approach calls for you to start at 2,500 feet. At what point, and what method would you use to determine when you could safely descend down prior to reaching the approach enviroment?

I'm surprised no one has addressed this. We did a lot of it in years past.
Firstly, are you in controlled airspace or not. If not then you can descend whenever you desire down to an altitude which gives you the 1000ft (2,000 moutainous) obstacle clearance 4 NM either side of your course. If you cannot determine that altitude safely OR if you are in controlled airspace and ATC cannot or does not give you lower, then you stay up until you arrive at a fix from which you can begin the approach. You may have to lose the excess altitude in a holding pattern if there is not enough room to get down after an Initial Approach Fix.
Before the days of almost universal RADAR coverage we (pilots) did a lot of this sort of thing.

~DC

 

[nosehair]

No need to fly at OROCA(Off Route Obstruction Clearance Altitude), that's the minimum altitude for that "sector" on the chart. Draw a line on a Sectional, measuure 4 nm either side of the true course line, add a thousand feet (2000 in mountainous terrain) to the highest obstacle and that is your MOCA.
It is only neccessary to stay within the bounderies of this line. How you navigate it is your business. Dead reckoning short distances with little wind is ok. Cross referencing VOR radials is even better.